They included Major Peake's best man, former Army Air Corps pilot Ian Curry, 50, who said: "I'm hugely excited about the launch. For me it's a once-in-a-lifetime opportunity to see a tremendously exciting thing and one of my best mates is on board. Tim and I are great mates, we've been pretty tight for 27 years."

Mr Curry, who now lives in Alabama in the US, revealed that the Peake family, including Major Peake's wife Rebecca, discussed whether being an astronaut was the right thing for Tim.

He said: "The family had a discussion about it and saw it as a big opportunity. They said, 'Go for it'. Rebecca's incredibly supportive and has been all the way through.

"Tim is an incredibly patient person. He maintains equilibrium terribly well. Things that would be too much for me, he just deals with."

It was all too much for one onlooker, Tim's youngest son Oliver, four. Sitting on the shoulders of his grandfather, Tim's father-in-law, he cried loudly, saying: "I want to go with Daddy."

He was consoled by his mother as he clutched a toy.

Major Peake and his crew mates waved and smiled before stepping on to the bus that will take them to the "suiting-up" building. There the trio will don their pressure suits before being transported to the launch pad.

As they were leaving, music was played - an old Russian song about a cosmonaut pining for home.

Later, the crew will salute the state commission - Cosmodrome officials - before being taken to Launch Pad 1 and climbing into the tiny Soyuz TMA-19 space capsule on top of the rocket.

It is the same historic spot Yuri Gagarin flew from to become the first man in space in 1961.

Major Peake is the first Briton to join the crew of the International Space Station (ISS). He is also the first fully British professional astronaut to be employed by a space agency.

Previous "Brits in space" have either been US citizens or had dual citizenship, or been on privately funded or sponsored trips.

Major Peake is employed by the European Space Agency (Esa) and sports a Union Flag on his sleeve.

The launch is scheduled for 11.03am UK time.

Rebecca and other family members had a final chance to wish Major Peake farewell at Building 252 where the crew were sitting with their pressure suits.

Major Peake had a private moment with his family from behind glass.

Then, at around 2.15pm local time, the three space-suited astronauts left to deliver the traditional salute to Cosmodrome officials and boarded the bus to the launch pad.

Smiling broadly, Major Peake waved to his sons from inside the bus, and gave them the thumbs up.